The roll bar according to one embodiment of the present invention comprises a pivotable tube bow which comprises two vertical pivot tubes, two stand tubes, which are fixedly connected to the frame of the construction machine, and two connection elements, via which the pivot tubes are connected to the stand tubes. The connection elements each comprise a stop surface, against which the pivot tube can be moved to, in particular pressed, in the operating position, a lock for clamping the pivot tube against the connection element in the operating position, a welding surface, to which the stand tube is materially bonded, and a pivot joint having a pivot axis, around which the pivot tubes are pivotable.
Construction machines are equipped with rollover protection devices or roll bars, which are fastened on the machine frame and extend upward, to protect an operator in case of a rollover of the machine. If the construction machine is equipped with a cab, the roll bar is normally integrated in the cab. In contrast, if the construction machine is implemented without a cab, which is often the case in smaller construction machines, the roll bar is typically implemented as freestanding, the roll bar generally being implemented as a U-shaped bow, whose free ends are fastened on the machine frame and whose crossbeam is situated essentially over the head of the operator. The roll bar is thus frequently the part of the construction machine which extends furthest upward.
Such an upwardly protruding roll bar can be disadvantageous during loading and during transport of the construction machine, for example. To overcome this problem, roll bars having folding mechanisms are known, which allow an upper area of the roll bar to be pivoted down and thus the height of the construction machine to be reduced. These folding mechanisms generally have locks, whereby the upper segment of the roll bar can be locked against the lower fixed segment of the roll bar in the folded-up state. Pivotable roll bars are known, in which the upper pivotable segment is connected using two pins to the lower, fixed segment. One pin is used as a hinge, which is situated fixed between the two segments. The other pin can be removed and thus allows the upper segment to be pivoted down. The locking pin is implemented parallel to the pivot axis of the hinge. It has a disadvantageous effect in this case that such a lock by pins is subject to play and the upper segment of the roll bar is deflected in the case of operationally-related vibrations. Furthermore, such a connection is complex to produce.
To overcome this problem, there are designs in which the upper segment of the roll bar is locked by multiple screw connections instead of a pin. It is disadvantageous in this case that the removal of the screws to pivot down the upper segment of the roll bar is only possible by using a tool. Furthermore, the screws are removed completely from the roll bar for pivoting down the upper segment and can easily be lost. The screw connection must also be produced using a predefined tightening torque and therefore can only be executed by trained personnel.
A pivotable roll bar is known from DE 10 2004 014 475 A1, which successfully overcomes the mentioned disadvantages of the prior art. There is nonetheless a need for a refinement of this roll bar, so that the weight and the costs can be reduced further.
The invention is therefore based on the object of providing a pivotable roll bar for a cab-less construction machine, in particular a vibration roller, which is implemented to save weight and cost with the greatest security.